My Morning Jacket and Band of Horses played host to an outdoor intergenerational jam fest last night, where the weather, magically, and the sound on the lawn, tragically, was not hot. I can't begin to understand why the built-in soundsystem above the lawn area of acoustically angelic Pritzker Pavilion in Millennium Park was not utilized (Union restrictions? A malfunction, perhaps?), but it was a huge disappointment to this writer and other megafans—including my dad and brother, who drove six hours from Southern Indiana for the show—who were only afforded, or could only afford, non-schmancy seats on the grass.

Band of Horses' set, which included new material from forthcoming Mirage Rock and hits "The Funeral," "No One's Gonna Love You," "Laredo," and others, would have been divine, had it not sounded like it was being piped through a cell phone from a public restroom. And unfortunately it took the length of that paltry output for us to stop thinking that it might get better and take matters into our own hands. After wading through the gender-respective lines for the park's public restrooms during the break, both my dad and I noticed that the concrete walls lining the ramp were not policed by security. And in what is perhaps his greatest act of anarchy, my 54-year-old father packed up his things from the lawn and made a semi-legal beeline for said walls.

"Dear Lord, there's a lot of hummus here," my younger brother, naive to the proclivities of urban outdoor concert goers, observed as we zig-zagged through the mess of blankets and boxed wine. And after hoisting ourselves atop the shorter of the two walls, we enjoyed a clear view and even clearer sonic stimulation as adorable Jim James and his Louisville crew blasted through an energized set spanning epic jammers from At Dawn, It Still Moves, Z and Circuital. We were even treated to a twangy cover of Elton John's "Rocket Man" (!) as well as Band of Horses' Ben Bridwell joining the MMJ guys onstage. "This is incredible!" my dad exclaimed through flashes of purple strobe lights toward the end of the evening. "But they HAVE to play 'One Big Holiday'." And then they did—with aplomb—much to the delight of my posse and the diverse crowd of retirees, undergrads and young moms surrounding our glorious spots atop the wall.